Two-piece ostomy appliances commonly consist of a collection pouch and an adhesive faceplate that are equipped with flexible plastic coupling rings which latch together and which permit a wearer to detach and replace the pouch component without removing the adhesive faceplate component from his/her body. The latching/unlatching actions typically involve limited flexing of one or both rings as they are urged together or pulled apart in axial directions in much the same manner as the lids of conventional plastic containers are closed and opened. However, in the case of an ostomy appliance, the wearer may be required to apply inward pressure to the sensitive peristomal area to latch the rings axially together and, conversely, to apply a pulling force to the same peristomal area when the rings are separated.
Although conventional ostomy coupling rings are joined or separated in axial directions, the sealing and/or latching forces are usually radially directed to maintain the surfaces of the parts in tight circumferential engagement. Mating the rings together is often difficult for users and generally requires a two-handed operation. That is because the procedure of joining the rings together normally involves initiating attachment at one point and then progressing in opposite circumferential directions until the rings have been squeezed together about their full circumferences. Since engagement progresses along two paths at the same time, the use of two hands is usually required. Furthermore, in such a system even initiating engagement may be difficult because the rings often have a tendency to slip out of alignment and obstruct circumferential progression of the coupling action.
With conventional coupling ring arrangements, there is often the further concern that the parts might become unintentionally detached, since all that would be required for such detachment is the occurrence of an axial pulling force of sufficient magnitude. Efforts to reduce the possibilities of unintended detachment have commonly involved increasing the stiffness of the rings or the extent of ring deformation when coupled, both of which also tend to make intentional attachment and detachment even more difficult for the wearer. That in turn increases the possibilities that a wearer, especially one who is elderly, infirm, or lacking in strength and dexterity, might conclude that complete coupling has been effected when in fact the rings have been only partially or imperfectly joined.
Conventional coupling ring arrangements have an additional shortcoming in that their interfacing surfaces are circular and may therefore permit rotational movement of a pouch ring with respect to a faceplate ring when the parts are fully coupled. Such rotation may result in a gradual "working off" of a pouch ring from a faceplate ring during physical activity or even when a patient rolls or turns about during sleep.
Accordingly, a main aspect of this invention lies in providing a two-piece ostomy appliance with coupling rings that do not require axially-directed movements for latching and unlatching and which provide full security against accidental detachment even when substantial axially-directed forces are exerted. Despite such high resistance to inadvertent detachment, the rings require only minimal force for intentional connection or separation, thereby eliminating or at least greatly reducing the manipulative problems often encountered by ostomates in attaching and removing prior two-piece appliances.
Unlike conventional coupling ring assemblies, the assembly of this invention locks the parts against independent relative rotation, thereby avoiding the possibility that rotational forces applied to a pouch might result in unintended separation. A further aspect of the invention lies in providing an assembly in which a fluid-tight preloaded seal is produced by axial flexion of one or both parts as they are urged transversely together into fully latched or interlocked condition.
Briefly, the appliance comprises a collection pouch and an adhesive faceplate equipped with relatively stiff but flexible plastic coupling rings for detachably securing the components together. The faceplate coupling ring has an upwardly-turned flange along a lower side thereof facing away from the faceplate to define an upwardly-directed first channel for slidably receiving a lower peripheral portion of the pouch coupling ring and, conversely, the pouch coupling ring has a downwardly-turned flange along its upper side facing away from the pouch to define a downwardly-directed channel for slidably receiving the upper peripheral portion of the faceplate coupling ring. Consequently, when the rings are urged transversely together, the channel of each respective ring receives a peripheral portion of the opposing ring to lock the rings against axial separation.
Most advantageously, the rings are polygonal in outline so that, when mated together, they are locked against relative rotation. A hexagonal shape is particularly effective because it also facilitates alignment of the coupling rings as they are urged together.
A fluid-tight seal is formed by mating engagement between inner rim portions of the respective rings located immediately adjacent the stoma openings of those rings. At least one, and preferably both, of the inner rim portions is axially offset to provide an axial preload for forceably maintaining the inner rim portions in fluid-tight engagement when the rings are coupled together. As the rings are urged transversely into alignment during a coupling operation, the inner rim portions are cammed into tensioned conditions and, when fully aligned, snap into sealing engagement to provide an audible and tactile indication that full coupling has occurred.
Other features, advantages, and objects of the invention will become apparent from the specification and drawings.